Mufid Abdul Qader Masha'al, half-brother of Hamas leader Khaled Masha'al, was released from prison four years early.
Mufid was sentenced in 2008 to twenty years behind bars for his work with with the "Holy Land" organization, the largest Muslim charity in the US, which served to fund the Hamas terror group.
He was convicted on three charges, including conspiracy to provide material support to a foreign terrorist organization, conspiracy to provide funds, goods and services to a terrorist, and conspiracy to launder money.
It is not clear whether Mufid was freed as part of an agreement ahead of a potential prisoner swap-ceasefire deal.
Khaled Masha'al is one of the most senior Hamas officials who has not been eliminated.
Four others were convicted and sentenced in addition to Mufid: Shukri Abu Baker, 50, and Ghassan Elashi, 55, will each spend the next 65 years behind bars. Another leader sentenced is the brother of Hamas politburo chief in Syria, Khaled Mashaal, according to the Al Arabiya news network.
Abdulrahman Odeh was sentenced to 15 years in prison for the same charges as Abdulqader. Mohammed El-Mezain was sentenced to 180 months in prison and three years of supervisory release for providing support to Hamas.